A formation of US Navy F-18E Super Hornets fly over northern Iraq after conducting a series of strikes against purported Daesh targets in Syria. (Photo by Reuters)

Russia has harshly criticized the United States for airstrikes on a Syrian military air base in the country’s eastern province of Dayr al-Zawr, arguing that such attacks threaten the implementation of the ceasefire meant to end hostilities in the conflict-ridden Arab country.

Russia’s Foreign Ministry said in a strongly-worded statement on Sunday that the strikes were “on the boundary between criminal negligence and direct connivance” with the Takfiri Daesh terrorists.

It said the incident was a result of Washington’s “stubborn refusal” to cooperate with Moscow in fighting Daesh, Jabhat Fateh al-Sham, al-Qaeda’s Syrian branch formerly known as al-Nusra Front, and “other terrorist groups.”

The Russia army said in a statement on Saturday that sixty-two Syrian soldiers had been killed and a hundred others injured in the strikes.

The statement added that two F-16 and two A-10 jets entered Syrian air space from Iraq to carry out the attacks.

Syria’s Foreign Ministry has called on the UN Security Council to condemn the American aggression, and force Washington not to repeat it and to respect Syria’s sovereignty plus unity of its land and people.

On September 9, Russia and the United States agreed on a milestone deal on the Syrian crisis after some 13 hours of marathon talks in the Swiss city of Geneva.

The deal, which began on September 12 and was initially agreed to last seven days, calls for increased humanitarian aid for those trapped inside the embattled northwestern city of Aleppo.

Under the terms of the ceasefire agreement, Russian and American fighter jets would launch joint airstrikes and pound the positions of Takfiri terrorist groups in Syria.

Syria back on the offensive after US raids

On Sunday, Syrian government soldiers, backed by allied fighters from popular defense groups, managed to wrest control over most of Daesh positions on the mountainous Jabal Therdeh area on Sunday after US-led coalition air strikes near Dayr al-Zawr airbase gave the extremists the chance to overrun the areas.

Syrian government soldiers walk in the damaged al-Farafira Souk in the government-held side of Aleppo, northwestern Syria, on September 16, 2016. (Photo by AFP)

The recapture of Jabal Therdeh area marks a great achievement for the Syrian army as it prevents Daesh terrorist from targeting military aircraft trying to take off or land at the airbase.

There are reports that Syrian and Russian fighter jets have struck the area around Dayr al-Zawr air base, militant-held areas as well as the road linking the embattled eastern Syrian city to the town of Mayadeen, which lies 45 kilometers (30 miles) to the southeast.

Elsewhere on the eastern outskirts of Aleppo, located some 355 kilometers (220 miles) north of the capital, Damascus, government forces repelled a Daesh offensive against the Syrian Air Academy.

An unnamed Syrian military official said army units clashed with Daesh militants, killing and wounding scores of the Takfiris in the process.

The official added that four pickup trucks equipped with heavy machine guns were also destroyed during the heavy fighting.

Syria has been gripped by foreign-backed militancy since March 2011. Over the past few months, the Takfiri militants active in the Arab country have suffered major setbacks as the Syrian army has managed to liberate several areas.

According to UN Special Envoy for Syria Staffan de Mistura, more than 400,000 people have been killed in the conflict in Syria. The UN has stopped its official casualty count in Syria, citing its inability to verify the figures it receives from various sources.